Slanted connector

ABSTRACT

A slanted connector and a method for mounting the same, having first connector means ( 20 ) extended in a first direction and second connector means ( 29   a - c ) extended in a slanted direction in relation to the first connector means ( 20 ). According to the invention the slanted connector comprises a first part ( 2 ) comprising the first connector means ( 20 ) and a second part ( 21   a - e ) comprising the second connector means ( 29   a - c ). The second part ( 21   a - e ) is connectable to the first connector means ( 20 ) and has a bent form in order to engage the first connector means ( 20 ) in a first direction and provide the second connector means ( 29   a - c ) protruding in at least one second direction slanted to the first direction, the second part ( 21   a - e ) having a circuit pattern to connect the first connector means ( 20 ) to the second connector means ( 29   a - c ).

TECHNICAL FIELD

[0001] The present invention relates to a slanted connector having firstconnector means extended in a first direction and second connector meansextended in a slanted direction in relation to the first connectormeans.

[0002] It also relates to a method for mounting a slanted connectorhaving first connector means extended in a first direction and secondconnector means extended in a slanted direction in relation to the firstconnector means.

RELATED ART

[0003] In electrical connections and circuits there are sometimes a needfor slanted connectors. There are such connectors available today and anexample of the construction of such a connector is shown in FIG. 1. Thisconnector comprises contact pins P18, which are slanted a certain angle.This angle is most often 90°. The bent divides the contact pins P18 intofirst connector means P20 and second connector means P29. This kind ofconnectors is very often provided at printed circuits. The secondconnector means P29 are soldered to a circuit card. In this example thepins forms a four times six matrix As can be seen from the figure thepins in each row are of different lengths.

[0004] U.S. Pat. No. 5,252,080 describes a press-fit printed circuitboard connector, which comprises an insulative body in two parts and aseries of right-angle metal pins. The structure of the connector is suchthat the connector does not require any dedicated tooling for mountingit on a board.

SUMMARY

[0005] One of the problems with these today available slanted connectorsis that the production process requires many different tools and workingmoments since different bending tools are needed for bending the pinswith different lengths. The bending of the pins could also result incracks in the pins. Another problem is that the different lengths of thepins result in a time shift of the signals to be transferred due to theresistance the pins. Yet another problem is that the end positions ofthe slanted pins to be connected to a printed circuit board not areprecise. The different lengths of the pins cause an uncertainty in theposition of the ends of the pins. This uncertainty makes it hard toperform surface mounting of the connector.

[0006] One object of the present invention is to simplify the mountingprocess of a slanted processor.

[0007] Another object of the present invention is to improve the truepositions of the pins of a slanted connector to be connected to aprinted circuit board.

[0008] Yet another object is to get rid of the time shift of the signalsto be transferred.

[0009] The above mentioned objects have been achieved by a slantedconnector of the initially defined kind, which is characterised by

[0010] a first part comprising the first connector means;

[0011] a second part comprising the second connector means and beingconnectable to the first connector means, the second part having a bentform in order to engage the first connector means in a first directionand provide the second connector means protruding in at least one seconddirection slanted to the first direction, the second part having acircuit pattern to connect the first connector means to the secondconnector means.

[0012] This slanted connector is much easier and faster to produce thanthe ones used today since the connector means does not need to be bent.Therefor also the exactness in the positions of the second connectormeans is improved and the risk for cracks in the pins is eliminated.

[0013] The objects have also been achieved by a method of the initiallydefined kind, which is characterised by the following steps:

[0014] creating a first part of the connector comprising the firstconnector means;

[0015] creating a separate second part of the connector comprising thesecond connector means, the second part having a bent form and receivingmeans for receiving the first connector means along the first directionand having the second connector means protruding in at least one wantedslanted direction, the second part connecting electrically the receivingmeans with the second connector means;

[0016] mounting the second part on the first part by connecting thefirst connector means to the receiving means;

[0017] placing the second connector means on a printed circuit board andsoldering the connector to the printed circuit board.

[0018] This method for mounting does not include any bending of theconnector means and therefor the mounting is quick and easy and the endpositions of the second connector means will be more exact than in todayexisting slanted connectors.

[0019] Preferably the second part is a bent printed circuit board havingthe circuit pattern as a printed pattern.

[0020] Suitably the second connector means are adapted to be connectedto a printed circuit board.

[0021] The second part comprises advantageously two plates, one firstplate and one second plate, integrally connected and angled to eachother.

[0022] Preferably the first plate is provided with through holes for thefirst connector means to fit into.

[0023] The second plate could be provided with through holes for thesecond connector means to fit into. Otherwise the second connector meanscould be integrally connected to the second plate, the second connectormeans being covered with a conducting cover.

[0024] Suitable the angle between the first plate and the second plateis a right angle, this implying that the angle between the firstconnector means and the second connector means is right.

[0025] The second part could preferably comprise conductors, eachconductor connecting at least one of the first connector means to atleast one of the second connector means.

[0026] Suitably all the conductors have the same length because if theconductors have the same length there is no problem with the time shiftof the signals to be transferred as mentioned above.

[0027] The second part could be built up as a multilayer printed wiringboard, having more than one layer, each layer containing at least one ofthe conductors.

[0028] Preferably the first part comprises a frame to receive the firstconnector means in supporting through holes providing a firm grip aroundeach first connector means to keep them in a fixed relationship to eachother, each connector means protruding from the frame a distance longenough to make electrical contact with through holes in the second part,when the first and second parts are mounted to each other.

[0029] The frame comprises suitably at least one guiding pin protrudingfrom the connector in the same direction as the second connector meansbut a greater distance. This at least one guiding pin guides theconnector to the right position when mounted on a circuit board.

[0030] The frame could comprise a cap for a robot to grab for automaticmounting of the connector on the circuit board.

[0031] Preferably the frame and the second part, besides the conductorsare made of an insulating material.

[0032] The number of first connector means and the number of secondconnector means is preferably the same. This implies that one firstconnector means corresponds to one second connector means.

[0033] A component could be provided on the second part, the componentbeing connected to one or more of the conductors. The component couldfor example be a delay unit, which controls the transferring time of thesignals.

[0034] The second plate can comprise two plates integrally connected andangled to each other, this implying that the outgoing pins areprotruding in two different directions.

[0035] The angle between the first plate and the second plate coulddiffer from 90°.

BRIEF DESCRIPTION OF THE DRAWINGS

[0036]FIG. 1 shows a side view of a prior art connector.

[0037]FIG. 2 shows a side view of a first embodiment of the connectoraccording to the invention

[0038]FIG. 3 shows a perspective view of the same connector as in FIG. 2in a separated position.

[0039]FIG. 4 shows a perspective view of the same connector as in FIGS.2 and 3 in a mounted position and also to be mounted on a printedcircuit board.

[0040]FIG. 5 shows the same connector as in FIG. 3 but having theslanted part partly in sections to show the different layers having theconnecting strips.

[0041]FIG. 6 shows a second embodiment of the connector according to theinvention in a side view cross section.

[0042]FIG. 7 shows the same connector as in FIG. 6 in a perspective viewfrom the backside.

[0043]FIG. 8a and b show a third embodiment of the connector accordingto the invention in a perspective view from different layers.

[0044]FIG. 9 shows a side view of a fourth embodiment of the connectoraccording to the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0045]FIG. 2, 3 and 4 shows a first embodiment of a slanted connectoraccording to the invention and represents the best mode of theinvention. The connector comprises a first part 2 and a second part 21a. The first part 2 comprises a frame 3 made of an insulating materialand, in this example, twenty-four incoming pins 20 as the first kind ofconnector means. The frame 3 comprises two plates 5 and 7 beingintegrally connected to each other so that they have an angle inrelation to each other. In the shown embodiment they are mounted atright angles to each other, but the angle could be varied. The incomingpins 20 are in this embodiment all of the same length, but it is commonthat for instance six of the pins 20 are longer than the rest. The pins20 are mounted in through holes 15 in the plate 7. The size of thethrough holes 15 is adapted to the size of the pins 20. The holes 15 arepreferably provided with some kind of gripping arrangement so that thepins 20 are fixedly positioned. The plate 7 has also a certain thicknessin order to support and grip the pins 20 firmly in their positions.

[0046] The connector is intended to be mounted on a printed circuitboard 9 and is therefor provided, at the end of the plate 7 opposite tothe plate 5, with two guiding pins 17 a and 17 b adapted to be placed inguiding openings in the board 9, one of the guiding openings 10 a beingvisible in FIG. 4. The guiding pins 17 a, 17 b protrude in the directionof the plate 7 and are positioned along a line perpendicular to theincoming pins 20. The number of guiding pins could of course be varied.

[0047] The plate 5 is thinner than the plate 7 and has the purpose toshield the pins 20 against mechanical damage. Thus the plate 5 is placedparallel to the pins 20 and has a longer extension than the pins 20 intheir incoming direction. The end of the plate 5, which is connected tothe plate 7 is provided with a cap 19 for a robot to grab when theconnector is automatically surface mounted on the printed circuit board9. The cap 19 is here shown to be shaped like a section of a circle butcould of course have other shapes adapted to be grabbed by a robot. Alsothe other side of the plate 5 has some cuts 8 provided near to grooves(not shown) for guiding a connecting part into the connector as commonin the art.

[0048] The second part 21 comprises two plates 23 a and 25 a beingintegrally, mechanically connected and angled to each other, the angledeciding how much the connector is slanted. In the shown embodiment theangle between the plates 23 a, 25 a is a right angle, but the anglecould be varied.

[0049] The plate 23 a is intended to be connected to the incoming pins20 protruding out from the plate 7 of the first part 2. It has hencereceiving means, which in the shown embodiment is a through hole 27 perpin 20 positioned to receive each pin 20 individually. Each hole 27 haselectrically leading sides, which could be an electrically leadinglining or the like making electrical contact with the pin 20. Each hole27 has also a size just adapted to the size of the pin 20 in order tohave a good grip together with good electrical contact. This is providedwhen the second part 21 a is mounted on the first part 2, as shown inFIG. 4. In order to make a press fit for good electrical contact theincoming pins 20 could be shaped like the letter H at their endsprotruding from the plate 7.

[0050] The plate 25 a is provided with a second kind of connector meanshere called outgoing pins 29 a on the side of the plate 25 a turnedtowards the printed circuit board 9. The number of the outgoing pins 29a is in this embodiment the same as the number of the incoming pins 20,but the numbers could differ. Each of the pins 29 a is in thisembodiment connected with an individual of the incoming pins 20. Thepins 29 a could be provided in the same matrix combination as theincoming pins 20 and they are in this embodiment each mounted, forexample soldered, in a metallized through hole 24 (FIG. 2) forelectrical connection. When the connector is mounted the outgoing pins29 a from the plate 25 a are preferably pointing in the same directionas the guiding pins 17 a, 17 b on the plate 7. However the guiding pins17 a, 17 b are most often longer than the outgoing pins 29 a since theyare to be positioned in the guiding openings, of which one 10 a isvisible in FIG. 4, in the printed circuit board 9. The outgoing pins 29a could be adapted for wave soldering and should then rest on contactpads 11 on the circuit board 9 to which the pins 29 a should besoldered. However the pins 29 a could also be adapted to be inserted inholes in the board to be soldered therein, as in somewhat oldertechniques.

[0051]FIG. 5 shows the second part 21 a of the first embodiment of thetwo parted slanted connector partly in cross section and in largerscale. Both the plates 23 a and 25 a are divided in four inner layers31A,33A,35A,37A and 31B,33B,35B,37B respectively, i.e. one layer foreach row of pins 20,29 a. Each layer in one of the plates 23 a, 25 acontinues in the same layer in the other plate 23 a, 25 a, such thateach layer is slanted. Each connection hole 27A in the first row ofholes for the pins 20 nearest the plate 5 is connected to an individualpin 28A of the pins 29 a in the outermost row of pins 29 a in the plate25 a by a conductive printed connector 30A in the outermost layer 31A,31B. Each connection hole 27B in the row next nearest to the plate 5 isconnected to an individual pin 28B of the pins 29 a in the nextoutermost row of pins 29 a in the plate 25 a by a conductive printedconnector 32A in the next outermost layer 33A, 33B etc.

[0052] It is also possible that each connection hole 27A in the firstrow of holes for the pins 20 nearest the plate 5 is connected to anindividual pin of the pins 29 a in the innermost row of pins 29 a in theplate 25 a by a conductive printed connector in the outermost layer 31A,31B. To make all the connectors equal in length each connection hole 27Bin the row next nearest to the plate 5 is connected to an individual pinof the pins 29 a in the next innermost row of pins 29 a in the plate 25a by a conductive printed connector in the next outermost layer 33A, 33Betc. When all the connectors have the same length there will be noproblem with the time shift as in the old technique.

[0053] The second part 21 a is thus a multilayer printed board, which isbent and has through holes 27,24 through all the layers 31A,33A,35A,37Aand 31B,33B,35B,37B. However the outermost surface layer of the plate 25a is a shielding layer hiding the through holes 24 and providing anattractive design of the second part 21 a.

[0054]FIG. 6 shows a second embodiment of the connector according to theinvention in a side view partly in cross section. It shows only a secondpart 21 b, since the rest of the connector is the same as in the firstembodiment. The second part 21 b comprises, as in the first embodimenttwo plates, 23 b and 25 b, which are integrally, mechanically connectedto each other. In this shown embodiment the angle between the plates 23b, 25 b is a right angle, but it could be varied.

[0055] The plate 25 b comprises outgoing pins 29 b, which are integrallyconnected to the plate 25 b and thus made of the same material, which isan insulating material. The outgoing pins 29 b are provided with aconductive cover 41 for making electrical contact to the printed circuitboard 9 when the connector is mounted on the printed circuit board 9.The plate 23 b is provided with holes 27 each having a metal lining 28as in the first embodiment.

[0056]FIG. 7 shows the same connector as in FIG. 6 in a perspectiveview. The view is from the backside and there it could be seen that inthis embodiment each hole 27 is connected to an individual pin 29 b by aconductor 43 provided at a one layer printed circuit board. The numberof the outgoing pins 29 b and the holes 27 could be twenty-four as inthe first embodiment, but for simplicity sake the number shown in thefigure is twelve. The number could even in this embodiment be differentfor the outgoing pins 29 b and the holes 27 this implying that eithereach hole 27 could be connected to a plurality of pins 29 b or each pin29 b could be connected to a plurality of holes 27.

[0057] The manufacturing of this slanted connector shown in FIGS. 6 and7 starts with the casting of the plates 23 b, 25 b and the outgoing pins29 b from an insulating material. The plates 23 b, 25 b and the outgoingpins 29 b are thus all integrally connected. Then the plates 23 b,25 band the pins 29 b are covered with a metal cover. The metal is thentaken away just to leave metal in the holes 27, on the pins 29 b and asconductors between the holes 27 and the pins 29 b. The conductors aremade equal in length to avoid the time shift problem occurring from thegreater resistance for the signals to be transferred in a long conductorthan in a short conductor. In this embodiment the conductors are madeequal in length by connecting suitable holes 27 to each pin 29 b suchthat the distance between the connected holes 27 and pins 29 b S alwaysis the same. Another method is to let the conductors wind when thedistance is short between the hole 27 and the pin 29 b to be connected.

[0058] In FIG. 7 it is also shown that a component 56, for example adelay unit could be integrated on the second part 21 b. The component 56is thus connected to one or more of the conductors 43 by connecting pins57. This kind of component could also be provided in all the otherembodiments. It is also possible to let the second part 21 b operate asa bent printed board provided with a plurality of components making asuitable signal processing of the signals from the incoming pins 20before they are fed to the outgoing pins 29 b connected to the circuitboard 9.

[0059]FIG. 8a and b show a third embodiment of the connector accordingto the invention in a perspective view from different layers. In thisembodiment a second part 21 c of the connector is built up of fourdifferent conductor layers as in the first embodiment The profile ofthis embodiment when only one layer is disposed looks like the profilein FIG. 6. The second part 21 c comprises like the second embodiment twoplates 23 c and 25 c integrally, mechanically connected to each other.In this shown embodiment the angle between the plates 23 c, 25 c is aright angle, but it could be varied.

[0060] The plate 25 c comprises outgoing pins 29 b, which are integrallyconnected to the plate 25 c and thus made of the same material, which isan insulating material. The outgoing pins 29 b are provided with ametallic cover for making electrical contact to the printed circuitboard 9 when the connector is mounted on it. The plate 23 c is providedwith metallized holes 27 as in the first embodiment. As in the secondembodiment only twelve holes 27 and pins 29 b are shown. The number ofholes 27 and pins 29 b could be varied.

[0061]FIG. 8a shows an inner layer 44 of the second part 21 c. Thislayer 44 is similar to the second embodiment but in this embodiment thelayer 44 comprises conductors 45 connecting only the holes 27 in thefirst row of holes for the pins 20 nearest the plate 5 with the pins 29b in the innermost row on the plate 25 c.

[0062]FIG. 8b shows a second layer 46 in the second part 21 c. Betweenthis second layer 46 and the first layer 44 an insulating layer has beendisposed. The second layer 46 comprises in this embodiment conductors 47from each individual of the holes 27 in the row second nearest to theplate 5 to each individual of the pins 29 b in the row next innermost onthe plate 25 c.

[0063] In the third layer the third row of holes is connected to thethird row of pins and so on.

[0064]FIG. 9 shows a side view of a fourth embodiment of the connectoraccording to the invention. Only a second part 21 d of the connector isshown since the first part 2 is the same as in the previous describedembodiments. The second part comprises, as in the other embodiments, twoplates 23 a,25 d which are integrally connected and angled to eachother. The angle between the plates 23 a,25 d is here shown to be biggerthan 90°. The angle could however be varied. Besides the angle, the onlydifference from the previous described embodiments is that the secondplate 25 d is divided into two plates 58,59 integrally connected andangled to each other. In this shown embodiment the angle is right but itcould be varied. Here it is shown that one of the four rows of theoutgoing pins 29 a is connected to the plate 59 and thus protruding in adifferent direction than the outgoing pins 29 a in the other three rows.The number of the outgoing pins 29 a connected to plate 58 and 59respectively could be varied. This fourth embodiment could of course beimplemented in all the other embodiments.

[0065] Although the invention is described with respect to fiveexemplary embodiments it should be understood that modifications couldbe made without departing from the scope thereof as expressed in theattached claims. Accordingly, the invention should not be considered tobe limited to the described embodiments, but defined only by thefollowing claims, which are intended to embrace all equivalents thereof.

1. A slanted connector having first connector means (20) extended in afirst direction and second connector means (29 a-c) extended in aslanted direction in relation to the first connector means (20),characterised by a first part (2) comprising the first connector means(20); a second part (21 a-e) comprising the second connector means (29a-c) and being connectable to the first connector means (20), the secondpart (21 a-e) having a bent form in order to engage the first connectormeans (20) in a first direction and provide the second connector means(29 a-c) protruding in at least one second direction slanted to thefirst direction, the second part (21 a-e) having a circuit pattern toconnect the first connector means (20) to the second connector means (29a-c).
 2. A slanted connector according to claim 1, characterised in thatthe second part (21 a-d) is a bent printed circuit board having thecircuit pattern as a printed pattern.
 3. A slanted connector accordingto claim 1 or 2, characterised in that the second connector means (29a-c) are adapted to be connected to a printed circuit board (9).
 4. Aslanted connector according to any one of the preceding claims,characterised in that the second part (21 a-e) comprises two plates, onefirst plate (23 a-d) and one second plate (25 a-e), integrally connectedand angled to each other.
 5. A slanted connector according to claim 4,characterised in that the first plate (23 a-d) is provided with throughholes (27) for the first connector means (20) to fit into.
 6. A slantedconnector according to claim 4 and 5, characterised in that the secondplate (25 a,25 d,25 e) is provided with through holes (24) for thesecond connector means (29 a,25 c) to fit into.
 7. A slanted connectoraccording to claim 4 and 5, characterised in that the second connectormeans (29 b) are integrally connected to the second plate (25 b,25 c),the second connector means (29 b) being covered with a conducting cover(41).
 8. A slanted connector according to any one of the precedingclaims, characterised in that the angle between the first plate (23 a-d)and the second plate (25 a,25 b,25 c,25 e) is a right angle, thisimplying that the angle between the first connector means (20) and thesecond connector means (29 a-c) is right.
 9. A slanted connectoraccording to any one of the preceding claims, characterised in that thesecond part (21 a-e) comprises conductors (30A,32A,43,45,47,63), eachconductor (30A,32A,43,45,47,63) connecting at least one of the firstconnector means (20) to at least one of the second connector means (29a-c).
 10. A slanted connector according to claim 9, characterised inthat all the conductors (43,45,47,63) have the same length.
 11. Aslanted connector according to claim 9 or 10, characterised in that thesecond part (21 a,21 c) is built up as a multilayer printed circuitboard, having more than one layer (31A,31B, 33A,33B, 35A,35B,37A,37B,44,46), each layer containing at least one of the conductors(30A, 32A,45,47).
 12. A slanted connector according to any one of thepreceding claims, characterised in that the first part (2) comprises aframe (3) to receive the first connector means (20) in supportingthrough holes (15) providing a firm grip around each first connectormeans (20) to keep them in a fixed relationship to each other, eachconnector means (20) protruding from the frame a distance long enough tomake electrical contact with through holes (27) in the second part (21a-e), when the first and second parts (2, 21 a-e) are mounted to eachother.
 13. A slanted connector according to claim 12, characterised inthat the frame (3) comprises at least one guiding pin (17 a,17 b)protruding from the connector in the same direction as the secondconnector means (29 a-c) but a greater distance.
 14. A slanted connectoraccording to claim 12 or 13, characterised in that the frame (3)comprises a cap (19) for a robot to grab for automatic mounting of theconnector on a printed circuit board (9).
 15. A slanted connectoraccording to any one of the claims 12-14 and 9-11, characterised in thatthe frame (3) and the second part (21 a-e), besides the conductors(30A,32A,43,45,47) are made of an insulating material.
 16. A slantedconnector according to any one of the preceding claims, characterised inthat the number of first connector means (20) and the number of secondconnector means (29 a-c) is the same.
 17. A slanted connector accordingto any one of the preceding claims, characterised in that a component(56), for example a delay unit, is provided on the second part (21 a-e),the component being connected to one or more of the conductors(30A,32A,43,45,47).
 18. A slanted connector according to any one of thepreceding claims, characterised in that the second plate (25 a-d,25 e)comprises two plates (58,59) integrally connected and angled to eachother, this implying that the outgoing pins (29 a-c) are protruding intwo different directions.
 19. A slanted connector according to any oneof the preceding claims, characterised in that the angle between thefirst plate (23 a) and the second plate (25 d) is not a right angle. 20.A method for mounting a slanted connector having first connector means(20) extended in a first direction and second connector means (29 a-c)extended in a slanted direction in relation to the first connector means(20), characterised by the following steps: creating a first part (2) ofthe connector comprising the first connector means (20); creating aseparate second part (21 a-e) of the connector comprising the secondconnector means (29 a-c), the second part (21 a-e) having a bent formand receiving means (27) for receiving the first connector means (20)along the first direction and having the second connector means (29 a-c)protruding in at least one wanted slanted direction, the second part (21a-e) connecting electrically the receiving means (27) with the secondconnector means (29 a-c); mounting the second part (21 a-e) on the firstpart (2) by connecting the first connector means (20) to the receivingmeans (27); placing the second connector means (29 a-c) on a printedcircuit board (9) and soldering the connector to the printed circuitboard (9).
 21. A method according to claim 20, characterised byconnecting a component (56) to one or more of the conductors(30A,32A,43,45,47,63) in the second part (21 b).
 22. A method accordingto claim 20 or 21, characterised in that the creating of the second part(21 b,21 c) comprises casting the second connector means (29 b) togetherwith the second part (21 b,21 c) in an insulating material and coveringthe second connector means (29 b) with a conducting cover (41).
 23. Amethod according to any one of the claims 20-22, characterised byproviding at least one guiding pin (17 a, 17 b) on the first part (2),the guiding pins (17 a,17 b) being adapted to be seated in at least oneguiding opening (10 a) when the second connector means (29 a-c) areplaced on a printed circuit board (9).
 24. A method according to any oneof the claims 20-23, characterised in that the electrical connecting ofthe receiving means (27) and the second connector means (29 a-c) isprovided by creating a bent, multilayer, printed board having electricalconductors (30A,32A,45,47) in different layers (31A,31B, 33A,33B,35A,35B, 37A,37B,44,46).
 25. A method according to any one of the claims20-24, characterised by providing the receiving means (27) of the secondpart (21 a-e) as through holes having electrically leading sides, eachhaving a size adapted to engage an individual of the first connectormeans (20) protruding from the first part, the through holes (27) of thesecond part (21 a-c) being positioned in the same configuration as thefirst connector means (20) in the first part (2).
 26. A method accordingto any one of the claims 20-25, characterised by providing the secondconnector means (29 a-c) in two different directions.